Dryer appliances generally include a cabinet with a drum rotatably mounted therein. During operation, a motor rotates the drum, e.g., to tumble articles located within a chamber defined by the drum. Dryer appliances also generally include a heater assembly that passes heated air through the chamber in order to dry moisture-laden articles positioned therein. Typically, an air handler or blower is used to urge the flow of heated air from chamber, through a trap duct, and to the exhaust duct where it is exhausted from the dryer appliance.
Conventional dryer appliances use two stainless steel sensor rods positioned within the chamber to detect the moisture content of a laundry load. More specifically, the two sensor rods are spaced apart and positioned such that the rotation of the drum causes clothes to contact both rods. The dryer appliance measures the resistance between the sensor rods or the conduction of electric current through the clothes contacting the rods to determine their moisture content.
However, current sensor rod systems do not provide precise moisture content detection, particularly at low moisture content levels. Typically, this inaccuracy is compensated for by increasing cycle time to achieve the desired final moisture content of the clothes. In addition, the signals generated by current sensor rod systems are very dependent of the type of load being dried, e.g., with delicate loads generating noisy signals and cotton loads generating smoother signals. As a result, heavy filtering processes are required, making the signal less reliable. The size of the load being dried also affects the output of current sensor rod systems.
Accordingly, an improved system and method for detecting the moisture content of a load of clothes is desirable. More specifically, a dryer appliance having more improved and reliable means for detecting the moisture content of clothes and adjusting the dryer appliance accordingly would be particularly beneficial.